Question

331/3% of a journey was covered at the speed of 20km/hr,one fourth at 30km/hr and the rest at 50km/hr.The average apeed for the whole journey was

Answer 1

Answer:

35 km/h

Step-by-step explanation:

Find the fraction of each part of the journey:

First part of the journey = 33 1/3% = 1/3 of the whole journey

Second part of the journey = 1/4 of the journey

Third part of the journey = 1 - 1/3 - 1/4 = 5/12 of the journey

Find the speed of each part of the journey:

First part of the journey = 20 km/h

Second part of the journey =30 km/h

Third part of the journey = 50 km/h

Find the ratio of the the speed:

Ratio = 1/3 : 1/4 : 5/12

(multiply by 12 through)

Ratio = 4 : 3 : 5

Find the average speed:

Average speed = [ (4 x 20) + (3 x 30) + (5 x 50) ] / ( 4 + 3 + 5)

Average speed = 420 / 12 = 35 km/h

Answer: The average speed is 35 km/h